I think I'll start from how Aftermath is different from WarZ. First of all it's crafting system was more advance, and as result we also created loot system that allowed us to break tons of "fluff" loot into 10 core crafting components. Aftermath had goals - like Town liberations tailored to group and team play. It added character permanent customizations, changed how armor and ammo works - basically improved components that been lacking in WarZ - we had to rewrite most of the game code for that.
Overall - if you can consider WarZ/DayZ/H1Z1 to be "survival 1.0", then Aftermath was 1.5 so to say - it had improvement, but overall was very similar.
Shattered Skies is a more on MMOFPS/PRG side.
In an essence it's a same - TPS/FPS survival full drop looter shooter. You kill monsters and other players, looking for best loot, unlock customizations and do things like this. But there're several key differences.
First of all it does have leveling for character. So more you play, more experience you accumulate, more skills and crafting recipes you'll be able to uncover. Those will create natural progression for your character, making some game features - boss fights, missions available to you.
Next crafting system was totally revamped. Not only recipes right now are available thru character progression, but they also are super useful for any players. Ie - we do not have recipes that would be like "okay we need to have something to fill list" type of stuff. Next goes crafting resources - all of them are available thru special "materials inventory" - they're persistent, you don't drop them on death. So it's very simple and intuitive to use system that actually offer for a change useful items. I mean lets take H1Z1 or Aftermath. As long as you're pretty high level - you don't need
**** like basic weapons or bow crafting
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. In Shattered Skies we have just only one recipe for gun - it's full auto uzi style "homebrew" pistol. And this recipe is not unlocked until you level 10 or so. So what it means is that after it unlocked even if you die and respawn with nothing at all - you'll always be able to craft basic gun right away. It saves you let say 15 minutes of gameplay each time you respawn. It will always be useful - even if you're at level 80
Character customization is totally different from WarZ. Your character have different parts that can be customized, and all customizations are persistent when unlocked. you also can change your appearance on fly.
Next goes fortification system that we basically borrowed from our failed Burstfire game project. You can check how it works here for example
https://www.youtube.com/watch?v=3n8PTTObOt4
So you'll be able on the fly craft fortifications and close off windows, holes in ceiling/walls, doorways in a buildings around the map crating your own fortress. We're adding some sort of "supply drop hunt" gameplay on top of that where crates with cool stuff appear on the map - so teams around the map know that in advance and move in to barricade and prepare building for supply drop arrival.
Next goes end game features - high level loot, boss summoning raids and fights, global world events. All those are happening in a game world - so things are not instanced, ie all players on the map can participate of they want.
And yes - game doesn't have micro transactions, paid expansions, things like this.
So bottom line - Shattered Skies is WarZ/DayZ/H1Z1/etc done RIGHT
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. Yes it took us 4 years to get here